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Open source

evaluate(pageFunction[, arg])

Executes JavaScript code in the page, passing the matching element of the locator as the first argument to the pageFunction and arg as the following arguments. It returns the value of the pageFunction invocation.

ParameterTypeDefaultsDescription
pageFunctionfunction or stringFunction to be evaluated in the page context.
argstring''Optional argument to pass to pageFunction.

Returns

TypeDescription
PromiseThe return value of pageFunction.

Example

JavaScript
JavaScript 
import { browser } from 'k6/browser';
import { check } from 'https://jslib.k6.io/k6-utils/1.5.0/index.js';

export const options = {
  scenarios: {
    browser: {
      executor: 'shared-iterations',
      options: {
        browser: {
          type: 'chromium',
        },
      },
    },
  },
};

export default async function () {
  const page = await browser.newPage();

  try {
    await page.goto("https://quickpizza.grafana.com", { waitUntil: "load" });

    await page.getByText('Pizza, Please!').click();

    await check(page, {
      'pizza name': async p => {
        const n = await p.locator('#pizza-name').evaluate((pizzaName, extra) => pizzaName.textContent + extra, ' Super pizza!');
        return n == 'Our recommendation: Super pizza!';
      }
    });
  } finally {
    await page.close();
  }
}